Coating composition

Abstract

A coating composition comprises (A) a polyol resin obtained by the reaction of a prepolymer of epoxy resin and phosphorus compound having at least one P-OH bond, such as acids of phosphorus, and one or more compounds having one or more amino groups reactive with the epoxy group, (B) a compound having more than one isocyanate groups or groups which change to isocyanate groups under hardening condition, and (C) a bituminous material and/or its substitute. This coating composition can be coated on rusty metal surfaces.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A coating composition which comprises (A) a polyol resin obtained by the reaction of an amino compound having at least one primary or secondary amino group with a prepolymer which prepolymer has been prepared by reacting an epoxy resin, with a phosphorus compound having at least P-OH group;   (B) a compound having more than one isocyanate group or groups which change to isocyanate groups under conditions effective for hardening the coating composition; and   (C) a material selected from the group consisting of coal tar, coal tar pitch, cut-back tar, bojuntan and asphalt wherein the reaction ratio of said phosphorus compound to said epoxy resin, by equivalents of the hydroxy groups of said phosphorus compound to the epoxy groups of said epoxy resin, is from 0.05 to 0.9; the reaction ratio of said amino compound to said prepolymer, by equivalents of groups of said amino compound that are reactive with the epoxy groups of said prepolymer, is from 1.1 to 0.7; the ratio of (A) to (B), by equivalents of the hydroxy groups of (A) to the isocyanate groups of (B), is from 0.4 to 1.2; and the weight ratio of (C) to (A) is from 0.5 to 2.     
     
     
       2. A coating composition as claimed in claim 1 in which said ratio of (A) to (B) is from 0.7 to 1.0, said ratio of said phosphorus compound to said epoxy resin is from 0.05 to 0.4, said reaction ratio of said amino compound to said prepolymer is from 1.0 to 0.9, and the average epoxide equivalent of said prepolymer is less than 3,000. 
     
     
       3. A coating composition as claimed in claim 1 in which said phosphorus compound is selected from the group consisting of acids of phosphorus, alkyl and hydroxyalkyl esters of said acids wherein said alkyl has 1 to 8 carbon atoms and salts of said acids. 
     
     
       4. A coating composition as claimed in claim 1 in which said phosphorus compound is selected from the group consisting of (1) acids of phosphorus selected from the group consisting of ortho-phosphoric acid, meta-phosphoric acid, pyro-phosphoric acid, phosphorus acid, polyphosphoric acid, phosphonic acid and phosphinic acid, (2) ethyl, propyl, n-butyl, 2-ethylhexyl, hydroxyethyl, hydroxypropyl, hydroxybutyl and hydroxypentyl esters of said acids, and (3) potassium, sodium, lithium, calcium, zinc, aluminum, tin and barium salts of said acids. 
     
     
       5. A coating composition as claimed in claim 1 in which said amino compound is a primary or secondary amine. 
     
     
       6. A coating composition as claimed in claim 1 in which said amino compound is selected from the group consisting of methylamine, ethylamine, propylamine, dibutylamine, ethanolamine, propanolamine, diethanolamine and diisopropanolamine. 
     
     
       7. A coating composition as claimed in claim 1 in which (B) is selected from the group consisting of tolylene diisocyanate, xylylene diisocyanate, diphenyl methane diisocyanate, hexamethylene diisocyanate, an adduct of 3 moles of tolylene diisocyanate and trimethylol propane and a prepolymer obtained from the foregoing compounds and containing isocyanate group. 
     
     
       8. A coating composition as claimed in claim 1 in which said amino compound is a monoamine having a single amino group. 
     
     
       9. A coating composition as claimed in claim 1 in which the reaction between said prepolymer and said amino compound is conducted at 60° to 150° C.